In the U.S.A., the primary orthodontic treatment procedure utilizes "external forces", whereas in Europe, the treatment procedures utilize "internal forces", attempting to harness the natural forces of the orofacial structures. This research is evaluating the therapeutic value of the Function Corrector of Dr. R. Frankel in comparison to Upper Headgear treatment in 7- to 9-year-old patients with a Class II, Division I malocclusion. Selected patients are randomly assigned to a treatment group, and treatment results will be assessed over a four-year period. The buccal shields of a function corrector exert a pulling effect on the basal periosteum which, Frankel postulates, stimulates bone growth in the narrow apical base region, giving teeth good osseous support for the widened dental arch. Eight squirrel monkeys have a specially fabricated appliance placed in the maxilla to test this hypothesis. Four monkeys will act as controls. Histological, radiographical, and gross studies of periosteal, pull, sagittal change and condylar growth will be conducted.